Clinical features of canine pulmonary veno‐occlusive disease and pulmonary capillary hemangiomatosis

Background Histologic features of pulmonary veno‐occlusive disease (PVOD) and pulmonary capillary hemangiomatosis (PCH) have been described in dogs but without a thorough clinical description. Objectives To report the clinical features, diagnostics, treatment, and outcome of dogs with histologic evidence of PVOD and PCH. Animals Fifteen pet dogs meeting histopathologic criteria of PVOD (occlusive remodeling of small‐sized to medium‐sized pulmonary veins) or PCH (alveolar capillary proliferation and congestion), or both. Methods Medical records of dogs with PVOD and PCH identified based on histopathologic features between 2003 and 2017 were retrospectively reviewed. Results Fifteen dogs met inclusion criteria of a histologic diagnosis of PVOD or PCH or both. Dogs were older (median 11 years) with no apparent breed or sex predisposition. Dogs presented with acute clinical signs (median 3 days), usually respiratory distress. Thoracic radiography (available in 10 dogs) revealed right cardiomegaly and patchy or diffuse interstitial to alveolar patterns, with 9 dogs having a normal left cardiac silhouette. In 5 dogs tested, pulmonary arterial hypertension (PAH) was documented. In all 3 dogs, thoracic computed tomography scans showed pulmonary arterial enlargement and perivascular diffuse nodular ground‐glass opacities. Ten of 15 dogs died within 1 day; median survival was 3 days. Conclusions and Clinical Importance In dogs with PAH, the inability to document left‐sided congestive heart failure and failure to identify another cause of signs of respiratory disease should increase suspicion for PVOD and PCH. With increased awareness of PVOD and PCH by clinicians and pathologists, dogs with compatible clinicopathologic features should be evaluated for these pulmonary vascular disorders.